Despite the endless stream of media hype these days (Paleo Diet, South Beach Diet, Atkins Diet, etc.), carbohydrates are not all that bad. At least not all of them.

One of the primary determinants of “good vs. bad” carbs is a measure called the Glycemic Index (GI). Simply put, the GI describes how quickly your body digests and absorbs certain carbohydrate-containing foods. Pure glucose (a simple sugar) has a GI value of 100, meaning that it is absorbed into your bloodstream very quickly. Peanuts, on the other hand, have a GI value of 10.

Are high-GI foods bad for you?

Well, it depends who you are and what your needs are. If you are an athlete who engages in prolonged intense exercise, then high-GI foods are your friends – they are the fastest way to replace your carbohydrate fuel stores and prevent the much dreaded “bonk”. But if you don’t exercise regularly, high-GI foods can be decidedly unfriendly.

High-GI foods lead to rapid spikes in blood sugar levels, which in turn lead to spikes in insulin levels. Insulin is a hormone released by your pancreas to shuttle excess blood sugar into your liver, muscles, and fat tissue. Unfortunately, insulin also stimulates an increase in blood triglycerides and LDL cholesterol, known risk factors for heart disease. Insulin spikes may also cause dramatic decreases in blood sugar, contributing to fatigue and hunger.

Low-GI foods are digested and absorbed more slowly by your body, resulting in a lower blood glucose and insulin response. Replacing high-GI foods with low-GI foods will not only reduce your risk for heart disease and perhaps type 2 diabetes, but will also help you maintain more even energy levels and prevent cravings between meals.

The take home message

High-GI foods are good and fine if you need them, but chronic consumption of high-GI foods can lead to an increased risk of heart disease and type 2 diabetes, as well as uneven energy levels and food cravings. Try to replace or combine high-GI foods with low-GI foods to mitigate your body’s blood glucose and insulin response.

Food for thought

What foods tend to have high-GI values? What foods have low-GI values?

When do you need high-GI foods? When/why are high-GI foods not such a good idea?

What modification could you make to your diet with regard to glycemic index?